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目的对市场采集的零售猪肉样品进行环丙沙星与头孢噻肟双耐药大肠杆菌检测和耐药机制分析。方法从陕西汉中(n=81)和北京(n=37)采集新鲜零售猪肉样品,对环丙沙星与头孢噻肟双耐药大肠杆菌进行分离、药敏和耐药机制分析。结果 22.0%(26/118)的零售猪肉样品检出环丙沙星与头孢噻肟双耐药大肠杆菌,以系统发生A群为主(12株),优势耐药谱型为AMP-CAZ-CTX-CIP-CHL-GEN-SXT-TET(n=14)和AMP-CAZ-CTXCIP-CHL-SXT-TET(n=7),所有菌株的拓扑异构酶喹诺酮耐药决定区中均有点突变,从12个菌株中检出质粒介导喹诺酮耐药机制;从24株产超广谱β-内酰胺酶大肠杆菌中共检出4个blaCTX-M型,其中blaCTX-M-55(n=22)为优势型。结论社区零售猪肉是环丙沙星与头孢噻肟双耐药大肠杆菌的重要储存库,其中blaCTX-M-55为三代头孢耐药的主要机制。
OBJECTIVE To analyze the drug resistance of ciprofloxacin and cefotaxime-resistant Escherichia coli in retail pork samples collected from the market. Methods Fresh retail pork samples were collected from Hanzhong of Shaanxi Province (n = 81) and Beijing (n = 37) to analyze the drug resistance and drug resistance mechanism of ciprofloxacin and cefotaxime. Results 22.0% (26/118) of retail pork samples were detected ciprofloxacin and cefotaxime double drug-resistant Escherichia coli group A (12 strains), the dominant drug resistance profile AMP-CAZ- There was a slight mutation in the quinolone-resistant determinants of all topoisomerase isolates in all isolates, CTX-CIP-CHL-GEN-SXT-TET (n = 14) and AMP- CAZ-CTXCIP-CHL-SXT-TET , And plasmid-mediated quinolone resistance mechanism was detected from 12 strains. Four blaCTX-M types were detected from 24 ESBLs-producing Escherichia coli strains, including blaCTX-M-55 (n = 22 ) For the dominant type. Conclusions Community retail pork is an important repository for ciprofloxacin and cefotaxime resistant E. coli. Among them, blaCTX-M-55 is the main mechanism of third generation cephalosporin resistance.